// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// This is a small utility that watches for and logs network changes.

#include <memory>
#include <string>
#include <unordered_set>

#include "base/at_exit.h"
#include "base/command_line.h"
#include "base/compiler_specific.h"
#include "base/json/json_writer.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/message_loop/message_loop.h"
#include "base/strings/string_split.h"
#include "base/values.h"
#include "build/build_config.h"
#include "net/base/network_change_notifier.h"
#include "net/proxy/proxy_config.h"
#include "net/proxy/proxy_config_service.h"
#include "net/proxy/proxy_service.h"

#if defined(USE_GLIB) && !defined(OS_CHROMEOS)
#include <glib-object.h>
#endif

#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
#include "net/base/network_change_notifier_linux.h"
#endif

#if defined(OS_MACOSX)
#include "base/mac/scoped_nsautorelease_pool.h"
#endif

namespace {

#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
// Flag to specifies which network interfaces to ignore. Interfaces should
// follow as a comma seperated list.
const char kIgnoreNetifFlag[] = "ignore-netif";
#endif

// Conversions from various network-related types to string.

const char* ConnectionTypeToString(
    net::NetworkChangeNotifier::ConnectionType type)
{
    switch (type) {
    case net::NetworkChangeNotifier::CONNECTION_UNKNOWN:
        return "CONNECTION_UNKNOWN";
    case net::NetworkChangeNotifier::CONNECTION_ETHERNET:
        return "CONNECTION_ETHERNET";
    case net::NetworkChangeNotifier::CONNECTION_WIFI:
        return "CONNECTION_WIFI";
    case net::NetworkChangeNotifier::CONNECTION_2G:
        return "CONNECTION_2G";
    case net::NetworkChangeNotifier::CONNECTION_3G:
        return "CONNECTION_3G";
    case net::NetworkChangeNotifier::CONNECTION_4G:
        return "CONNECTION_4G";
    case net::NetworkChangeNotifier::CONNECTION_NONE:
        return "CONNECTION_NONE";
    case net::NetworkChangeNotifier::CONNECTION_BLUETOOTH:
        return "CONNECTION_BLUETOOTH";
    default:
        return "CONNECTION_UNEXPECTED";
    }
}

std::string ProxyConfigToString(const net::ProxyConfig& config)
{
    std::unique_ptr<base::Value> config_value(config.ToValue());
    std::string str;
    base::JSONWriter::Write(*config_value, &str);
    return str;
}

const char* ConfigAvailabilityToString(
    net::ProxyConfigService::ConfigAvailability availability)
{
    switch (availability) {
    case net::ProxyConfigService::CONFIG_PENDING:
        return "CONFIG_PENDING";
    case net::ProxyConfigService::CONFIG_VALID:
        return "CONFIG_VALID";
    case net::ProxyConfigService::CONFIG_UNSET:
        return "CONFIG_UNSET";
    default:
        return "CONFIG_UNEXPECTED";
    }
}

// The main observer class that logs network events.
class NetWatcher : public net::NetworkChangeNotifier::IPAddressObserver,
                   public net::NetworkChangeNotifier::ConnectionTypeObserver,
                   public net::NetworkChangeNotifier::DNSObserver,
                   public net::NetworkChangeNotifier::NetworkChangeObserver,
                   public net::ProxyConfigService::Observer {
public:
    NetWatcher() { }

    ~NetWatcher() override { }

    // net::NetworkChangeNotifier::IPAddressObserver implementation.
    void OnIPAddressChanged() override { LOG(INFO) << "OnIPAddressChanged()"; }

    // net::NetworkChangeNotifier::ConnectionTypeObserver implementation.
    void OnConnectionTypeChanged(
        net::NetworkChangeNotifier::ConnectionType type) override
    {
        LOG(INFO) << "OnConnectionTypeChanged("
                  << ConnectionTypeToString(type) << ")";
    }

    // net::NetworkChangeNotifier::DNSObserver implementation.
    void OnDNSChanged() override { LOG(INFO) << "OnDNSChanged()"; }
    void OnInitialDNSConfigRead() override
    {
        LOG(INFO) << "OnInitialDNSConfigRead()";
    }

    // net::NetworkChangeNotifier::NetworkChangeObserver implementation.
    void OnNetworkChanged(
        net::NetworkChangeNotifier::ConnectionType type) override
    {
        LOG(INFO) << "OnNetworkChanged("
                  << ConnectionTypeToString(type) << ")";
    }

    // net::ProxyConfigService::Observer implementation.
    void OnProxyConfigChanged(
        const net::ProxyConfig& config,
        net::ProxyConfigService::ConfigAvailability availability) override
    {
        LOG(INFO) << "OnProxyConfigChanged("
                  << ProxyConfigToString(config) << ", "
                  << ConfigAvailabilityToString(availability) << ")";
    }

private:
    DISALLOW_COPY_AND_ASSIGN(NetWatcher);
};

} // namespace

int main(int argc, char* argv[])
{
#if defined(OS_MACOSX)
    base::mac::ScopedNSAutoreleasePool pool;
#endif
#if defined(USE_GLIB) && !defined(OS_CHROMEOS)
    // g_type_init will be deprecated in 2.36. 2.35 is the development
    // version for 2.36, hence do not call g_type_init starting 2.35.
    // http://developer.gnome.org/gobject/unstable/gobject-Type-Information.html#g-type-init
#if !GLIB_CHECK_VERSION(2, 35, 0)
    // Needed so ProxyConfigServiceLinux can use gconf.
    // Normally handled by BrowserMainLoop::InitializeToolkit().
    g_type_init();
#endif
#endif // defined(USE_GLIB) && !defined(OS_CHROMEOS)
    base::AtExitManager exit_manager;
    base::CommandLine::Init(argc, argv);
    logging::LoggingSettings settings;
    settings.logging_dest = logging::LOG_TO_SYSTEM_DEBUG_LOG;
    logging::InitLogging(settings);

    // Just make the main message loop the network loop.
    base::MessageLoopForIO network_loop;

    NetWatcher net_watcher;

#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
    base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
    std::string ignored_netifs_str = command_line->GetSwitchValueASCII(kIgnoreNetifFlag);
    std::unordered_set<std::string> ignored_interfaces;
    if (!ignored_netifs_str.empty()) {
        for (const std::string& ignored_netif :
            base::SplitString(ignored_netifs_str, ",", base::TRIM_WHITESPACE,
                base::SPLIT_WANT_ALL)) {
            LOG(INFO) << "Ignoring: " << ignored_netif;
            ignored_interfaces.insert(ignored_netif);
        }
    }
    std::unique_ptr<net::NetworkChangeNotifier> network_change_notifier(
        new net::NetworkChangeNotifierLinux(ignored_interfaces));
#else
    std::unique_ptr<net::NetworkChangeNotifier> network_change_notifier(
        net::NetworkChangeNotifier::Create());
#endif

    // Use the network loop as the file loop also.
    std::unique_ptr<net::ProxyConfigService> proxy_config_service(
        net::ProxyService::CreateSystemProxyConfigService(
            network_loop.task_runner(), network_loop.task_runner()));

    // Uses |network_change_notifier|.
    net::NetworkChangeNotifier::AddIPAddressObserver(&net_watcher);
    net::NetworkChangeNotifier::AddConnectionTypeObserver(&net_watcher);
    net::NetworkChangeNotifier::AddDNSObserver(&net_watcher);
    net::NetworkChangeNotifier::AddNetworkChangeObserver(&net_watcher);

    proxy_config_service->AddObserver(&net_watcher);

    LOG(INFO) << "Initial connection type: "
              << ConnectionTypeToString(
                     net::NetworkChangeNotifier::GetConnectionType());

    {
        net::ProxyConfig config;
        const net::ProxyConfigService::ConfigAvailability availability = proxy_config_service->GetLatestProxyConfig(&config);
        LOG(INFO) << "Initial proxy config: "
                  << ProxyConfigToString(config) << ", "
                  << ConfigAvailabilityToString(availability);
    }

    LOG(INFO) << "Watching for network events...";

    // Start watching for events.
    network_loop.Run();

    proxy_config_service->RemoveObserver(&net_watcher);

    // Uses |network_change_notifier|.
    net::NetworkChangeNotifier::RemoveDNSObserver(&net_watcher);
    net::NetworkChangeNotifier::RemoveConnectionTypeObserver(&net_watcher);
    net::NetworkChangeNotifier::RemoveIPAddressObserver(&net_watcher);
    net::NetworkChangeNotifier::RemoveNetworkChangeObserver(&net_watcher);

    return 0;
}
